1. Field of the Invention
The present invention relates to an improved disconnect device, and more particularly, to a device for disconnecting a driven device, such as a generator, from the driving source such as, for example, an aircraft engine.
2. Description of the Prior Art
In aircraft applications, the electrical system for supplying the electrical needs of the vehicle customarily incorporates one or more generators which are either directly driven from the engine or through a speed-reducing gearbox. These generators are customarily operated at high speeds which often are in excess of 10,000 rpm. Occasionally, one or more of the generators must be disconnected from the driving source lest serious damage be done to the generators and electrical system because of some malfunction which has already occurred or is about to occur. For example, the generator must be disconnected from the driving source if there is an actual or incipient bearing failure, excessive vibration, engine overspeed, excessive oil temperature, etc. Whenever any of these or other malfunctions occurs, rapid disconnect of the generator from the driving source is required to avoid serious damage to the equipment and to the system. Usually, sensors of various types are strategically distributed throughout the aircraft to sense the occurrence or incipient occurrence of these various conditions. These sensors generate a signal which produces an indication such as the lighting of a warning light, actuation of a buzzer, or the like, on the pilot's instrument panel. When the warning device is energized to indicate the malfunction, the pilot actuates a disconnect mechanism which removes the generator from the driving source.
Hitherto, two basic types of disconnect devices have been generally available: devices which can be classified generally as resettable and nonresettable. The resettable devices are of the type in which the generator, once disconnected, can be reconnected to the driving source without in any way disassembling or replacing components of the device. The non-resettable disconnects, on the other hand, usually involve rupturing, shearing, or fracturing of a connection between the driving source and the generator, and therefore require disassembly and replacement of certain components before the generator can be again placed on line. Both types of disconnect devices, while useful in many applications and circumstances, are subject to a number of failings which limit their utility. The resettable devices can be complex and bulky in construction since not only must they provide for disconnecting the generator, but they must also allow reconnection while the device still is rotating. Furthermore, the resettable devices require a substantial number of interacting components so that the reliability of the devices is often less than might be desired. The nonresettable disconnects, on the other hand, while simple in construction, also have some shortcomings. The replacement of parts which have been separated or sheared and the resetting of the shearing mechanism often take substantial amounts of time to accomplish. Consequently, a need exists for a simple but lightweight disconnect which has both resettable and replaceable components and which is capable of operating at high speeds and in which the disconnect function is carried out rapidly, effectively, and at any angular position of the rotating members, and in which the reset function is accomplished with a minimum of time and with a minimum of replacement parts.
It is therefore an object of the present invention to accomplish the above with a minimum of parts and in an efficient, reliable, and cost-effective fashion.
It is a further object of the present invention to provide a combination resettable and replaceable shaft disconnect arrangement in which the member which is ruptured to disconnect the shafts is inexpensive and is easily replaced.
Other objects and advantages of the invention will become apparent as the description thereof proceeds.